1. Field of the Invention
The present invention relates to an optically active stilbene compound used as a liquid crystal material; to an intermediate for, and to a method for producing the optically active stilbene compound; and to a liquid crystal composition containing the optically active stilbene compound.
2. Discussion of Background
At the present time, liquid crystal materials are widely used as display elements. Almost all these liquid crystal display elements, however, are the TN (Twisted Nematic) type of display systems which utilize nematic liquid crystals. This type of liquid crystal display element has the drawback that its response speed is low, inasmuch as the response speeds obtained are in the order of several seconds, at the best.
For this reason, various types of liquid crystal display systems based on other principles have been tried in place of the TN display system. One such system uses a strongly dielectric liquid crystal material (N. A. Clarks et al.; Applied Phys. Lett. 36, 899 (1980)). This system, which uses a strongly dielectric chiral smectic phase, and, in particular, a chiral smectic C phase, is attracting considerable interest as a high speed optical switching device. This type of highly dielectric liquid crystal material is already well known, for example, as disclosed in Japanese Laid-Open Patent Application 64-70455, but does not adequately provide the desired characteristics.